Greenhouse Gas Emissions

Greenhouse gas emissions from the agricultural sector account for six
percent of the total U.S. greenhouse emissions. However, agricultural
activities account for 72% of the total U.S. nitrous oxide (N2O)
emissions (EPA, 2006). Researchers at Russell Ranch are investigating
the effect of different practices and crop systems on greenhouse gas
emissions. One important finding is that reducing tillage substantially
decreases greenhouse gas emissions through reduced fuel use.
Research at Russell Ranch has shown that winter cover crops increase
N2O emission under furrow irrigation (Fig. 14). Sub-surface drip
eliminates the increase in N2O emission seen with cover crops using
furrow irrigation. Research at LTRAS suggests that the conversion to
sub-surface drip irrigation from furrow irrigation has the potential to
reduce greenhouse gas emissions. This is significant because many
studies suggest that planting cover crops can lead to an increase in
both CO2 and N2O emissions but when managed with sub-surface drip
irrigation this effect may be reduced (Kallenbach, 2008).